/Engine/Plugins/Runtime/GameplayAbilities/Source/GameplayAbilities/Public/AbilitySystemComponent.h
This is a helper function - it seems like this will be useful as a blueprint interface at the least, but Level parameter may need to be expanded
[FActiveGameplayEffectHandle](API\Plugins\GameplayAbilities\FActiveGameplayEffectHandle) ApplyGameplayEffectToSelf ( const [UGameplayEffect](API\Plugins\GameplayAbilities\UGameplayEffect) * GameplayEffect, float Level, const [FGameplayEffectContextHandle](API\Plugins\GameplayAbilities\FGameplayEffectContextHandle) & EffectContext, [FPredictionKey](API\Plugins\GameplayAbilities\FPredictionKey) PredictionKey )